Answer:
B 
Step-by-step explanation:
In order to get the same denominator, we need to multiply the second fraction by (b+2) in the numerator and denominator.
We will end up in something like this :
I just timed the second fraction by b+ 2 and then i added them together.
Therefore, we will get 
now factoring the numerator we will end like this

we will then end up with the answer.
Hope this helps.
The solution is in the attached file
Answer:
Follows are the solution to the given points:
Step-by-step explanation:
In point a:
In this sense, describe what type of error I will be.
Type I error: to conclude that perhaps the mean bulb life would be less than three hours when it becomes (at least) 3 hours.
In point b:
Describe throughout this context what the Type II error becomes.
An error of type II: never assuming that its bulbs' mean lifetime is much less than 3 hours. three hours at least
In point c:
What error — type I and type II — would further impact the interaction between the manufacturer and the customer?
A Type II error is probably further problematic because it means that even the buyer will buy bulbs that do not last long.
11/12 - 7/9
=>taking L.C.M of the denominator
=>11/36 - 7/36
=>4/36
=>2/18=>1/9
4 times 8 tenths
1/10=1 tenth
8/10=8 tenths
4 times 8/10
4/1 times 8/10
(4 times 8)/(1 times 10)
32/10
16/5
5/5+5/5+5/5+1/5
1+1+1+1/5
3+1/5
3 and 1/5